The 1995 Trans Am LT1's factory horsepower rating is 275 hp. Adding MSD ignition coils and Flowmaster mufflers will *increase* horsepower slightly, but not dramatically. You're unlikely to see more than a 10-15 horsepower gain, possibly less. Many factors influence the exact increase, including the specific MSD coil and Flowmaster muffler used, as well as the overall condition of the engine.
Therefore, a reasonable estimate would be 285-290 hp, but it could be a bit higher or lower depending on the variables mentioned. It's not a significant jump from the stock rating.
